Feed device with fluid activated rippling sheets



July 30, 1963 M. c. HEINZE 3,099,494

FEED DEVICE WITH FLUID ACTIVATED RIPPLING SHEETS Filed June 6, 1961 [I l 1 I1 I I IN VEN TOR.

ATTOIFA/EYS United States Patent 3,099,494 FEED DEVICE WITH FLUID ACTIVATED RIPPLlNG SHEETS Marvin C. Heinze, Clark, N.J., assignor to FMC Corporation, a corporation of Delaware Filed June 6, 1961, Ser. No. 115,260 3 Claims. (Cl. 302-31) This invention relates to a feeding device for moving material which normally tends to build up on the walls of the device.

When moist particles, or particles having a tendency to cake, are contained in a storage container or must be passed through an open-end chamber, the particles tend to agglomerate, or become compacted, or adhere to the walls of the container. This often results in stoppage of flow or complete blockage of the discharge end of the container.

Prior devices for overcoming these difliculties have involved periodically-pulsating mechanisms within the container. Such mechanisms are mechanically activated metal plates, inflatable elastic sheets alternately inflated and deflated by a fluid pressure means, and a controlled gas flow to fluidize the particles have all been used. These prior art devices have been expensive to operate, complex in design and often the cause of further difliculties of operation.

This invention has the following objects: to provide a novel, simply-designed apparatus for preventing moist or calcing materials from adhering to the inner walls of a container; to provide a simple device capable of causing vibratory movement within a container; to provide a feeding device having vibratory sheets which will not permit wet particles to agglomerate or compact at the discharge end; and to provide a container apparatus in which contained material can be eflectively discharged in a steady flow.

Other objects will become apparent as fuller description of the invention is given.

According to this invention, the apparatus, designed to accomplish the above objects, is a feeding device consisting of a container with an open upper end, a discharge opening adjacent its lower end, a plurality of flat sheets of flexible material aflixed along the upper edge thereof to the inner walls of the container above the discharge opening, and means under the sheets for introducing a constricted flow of a fluid of sufficient force to cause the flexible sheets to vibrate in such a manner that moist particles falling through the container are prevented from adhering to the sides.

In the accompanying drawings, which are merely illutrative of one form of the device of this invention,

FIGURE 1 is a top plan view of the device;

FIGURE 2 is a section through lines 22' of FIG. 1.

The operation of the apparatus will be described in conjunction with these drawings. In FIGURES 1 and 2, a container is open at the top to receive the material which passes downward by gravity. Attached to the flat inner walls of the container, are extendible or flexible sheets 11, secured by metal strips or other means 12 along the uprn-ost edge of the sheet. Directly beneath each sheet are openings 13 in the container w-al-ls through which may pass some fluid under pressure, through conduits 14. Air is a typical fluid which may be passed through a common valved duct 15, to the individual conduits. The force of the air causes the flexible sheets to vibrate outwardly agitating the flow of the particles downward in a peristaltic fashion, thereby preventing the particles from adhering to the walls of the container.

When the container is a hopper-like chute, as shown in FIGURE 2, it is preferred to position at least one set of sheets close to the discharge end to keep the outlet continually clear. As wet or caking material tends to arch or form bridges and consequently to impede the outflow, particularly Where the outflow and is narrower than the feed end, prevention of these arches is necessary.

The sheet which may be either an inert flexible plastic sheet or a flexible metal sheet is fixed to the container Wall by any convenient means. A bolted metal band across the upper edge has been found to be acceptable. The band should be as thin as possible with protrusion of the heads of the fastening devices so that the next higher overlapping sheet will protrude away from the container wall as little as possible. Use of a band having bolts stud-welded to the surface in contact with the plastic sheet is preferred.

The opening for the fluid should be so positioned below the sheet to obtain the maximum vibration at minimum pressure. To accomplish this, the fluid access is preferably placed from A to /2 the length of the sheet from the upper edge. Of course, this distance may be even greater causing air to be introduced below the midline of the sheet, but then less agitation will result.

It will be noted [that the operation may run continuously so that air or other fluid will enter the container at all times. The vibration of the sheet is therefore not caused by varying the fluid pressure but merely by applying a steady pressure. A simple compressed air-line is the only external mechanism required. Any inert gas or liquid could be equally applied if required. The sheet responds to the fluid pressure by a rippling motion, continually receiving and spilling the fluid. This rippling vibration dislodges any caking which may occur and prevents adhesion of the particles to the sides.

Of secondary effect is the force of the fluid upon the particles, as well as upon the sheet. Since the sheet permits the fluid to pass into the container, some blow-down action is also to be expected. If the air pressure, for example, is very high, the particles will, in turn, gravitate more rapidly.

The sheets may be made of any substance ordinarily inert to the conditions within the container and to the particles that are passed through. Flexible metal sheets have been mentioned earlier as suitable. Natural and synthetic rubbers, polyfluorocarbons, polyvinyl chlorides, linear polyamides, polyethylene, poly(ethylene) aromatic esters, and other thermoplastic sheeting material may also be used in this invention. The surface quality of the sheet should be smooth and preferably slick to prevent material buildup on it. Of particular interest is polyrtetrafluoroethylene sheeting which possesses excellent flexibility over a wide temperature range and has a very slick surface. The almost complete inertness of this material tocommon commercial reagents makes it particularly preferred in this invention.

In one preferred embodiment of this invention, wet polydiallyl phthalate filter cake was dropped into a hopper, similar to that shown in the drawings, approximately 2 feet wide. Six sheets of Du Pont Corporation commercial-grade Teflon were clamped along the walls of the container, substantially as depicted in the drawings. Each sheet, about 2 feet square, was clamped along the upper edge by l-inch plates and two inch machine bolts. The fluid openings were positioned in the center of each sheet, about /3 of the length from the plate. An air pressure of p.s.i.-g. was passed into each opening. The vibration of the sheets caused the particles to discharge with no material buildup on the walls of the hopper.

Since all areas of the container walls must be reached by the vibratory action of the sheets, it is important that rthere be no dead spots. To prevent areas of possible material buildup on the container walls, the sheets should be preferably positioned or designed so as to overlap the next descending sheet. Where the general shape of the container is circular, fiat metal surfaces must be installed inside the container against which the flat, flexible sheets may rest so that, in.- eifeot, a pyramidal surface results. Clearly more sheets will be needed in such an arrangement than in square or rectangular containers. In small rectangular containers, the width of the sheet may be approximately the width of the container.

The fluid apertures, as stated earlier, need not be limited to the upper portion of the sheet, nor need there be only one. A series of ponts may be arranged beneath each sheet. If, in fact, the sheet is large enough so that only one or two sheets will be required, depending on the nature and volume of the container, many ports may be placed in pre-designed positions to cause greater vibration. The port may be a simple opening in the wall to which is attached a threaded portion, such as a nipple, for introducing an air-pipe.

The fluid most convenient to use is air. The system may, however, be of the type in which an inert gas blanket is desirable, and such a gas as nitrogen may be applied. If the feed material is being passed into a drier the vibratory action of the sheets will cause the caked material to break up into smaller, more easily dried particles. Any number of other variations of this invention will be suitable in like operations.

This apparatus permits convenient handling of wet, or caking materials when being stored or passed through a container. Such containers as collection chutes, storage silos, bagging machines, driers and other types of storage vessels and feeders can be readily adapted to this invention by simple means.

Based upon this description and upon obvious variations within the scope of this invention, I claim:

1. A feeding device for caking solids comprising a container having 4 (1) an open upper end for receiving said solids, (2) a lower discharge end, (3) an inner lateral surface having positioned thereon a plurality of thin, flexible sheets substantially paral- 5 'l-el, when at rest, to the said lateral surface, and fixed to said lateral surface along one direction thereof and only at the upper edge of each sheet, the remaining edges being unfixed and free to move in such a manner that the entire sheet below the fixed edge can be extended away from said surface, and (4) a fluid-introducing means, having access through the lateral surface to a point A to /2 of the length of the sheets from their tfixed upper edges directly beneath each of said sheets, whereby the introduction of a fluid under pressure causes the free edges of the sheets to extend away from the lateral surface so that only the fixed upper edge is in contact with the lateral surface. 2. The feeding device 'of claim 1 in which the fluid is air.

3. The feeding device of claim 1 in which the sheets are so positioned that each sheet overlaps the next descending sheet.

References Cited in the file of this patent UNITED STATES PATENTS 544,969 Dodge Aug. 20, 1895 1,134,600 Filson Apr. 6, 1915 1,570,795 Tainton Jan. 26, 1926 1,759,983 Huston May 27, 1930 2,353,346 Logan July 11, 1944 2,686,083 Hampton et al Aug. 10, 1954 2,715,550 Shields Aug. 16, 1955 2,924,487 Stambera Feb. 9, 1960 

1. A FEEDING DEVICE FOR CAKING SOLIDS COMPRISING A CONTAINER HAVING (2) A LOWER DISCHARGE END, (3) AN INNER LATERAL SURFACE HAVING POSITIONED THEREON A PLURALITY OF THIN, FLEXIBLE SHEETS SUBSTANTIALLY PARALLEL, WHEN AT REST, TO THE SAID LATERAL SURFACE, AND FIXED TO SAID LATERAL SURFACE ALONG ONE DIRECTION THEREOF AND ONLY AT THE UPPER EDGE OF EACH SHEET, THE REMAINING EDGES BEING UNFIXED AND FREE TO MOVE IN SUCH A MANNER THAT THE ENTIRE SHEET BELOW THE FIXED EDGE CAN BE EXTENDED AWAY FROM SAID SURFACE, AND 